A workpiece support device can be formed by utilizing a plurality of parallel rods or pins, provided in an array of columns and rows with free ends of the rods or pins lying either in a plane which defines a support surface or alternatively retracted therefrom to form a recess in the support surface. A workpiece on which an operation is to be performed can be supported by the support surface even though it has projections or irregularities on the face which is towards the support surface since such projections or irregularities can be accommodated in the recesses formed by retracted ones of the rods. The workpiece may, for example, be a printed circuit board which already carries circuit components on one side thereof and the other side of which is to have an operation effected thereon such as a printing operation, solderflow to secure the circuit components in place or affixing of further circuit components.
In one embodiment of a device utilizing the prior art, the non-free end of each rod is coupled to a respective piston within a respective cylinder, with all cylinders in each row having their upper ends connected to a pressure source and their lower ends connected to a pressure source, both sources controlled by one respective solenoid valve, and with each rod controlled by a control means.